[tor-bugs] #9166 [Tor]: Write a UTP-based channel implementation

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#9166: Write a UTP-based channel implementation
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 Reporter:  nickm          |          Owner:                  
     Type:  defect         |         Status:  new             
 Priority:  normal         |      Milestone:  Tor: unspecified
Component:  Tor            |        Version:                  
 Keywords:  tor-relay utp  |         Parent:  #9165           
   Points:                 |   Actualpoints:                  
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Changes (by karsten):

 * cc: robgjansen (added)


Comment:

 I just finished new Shadow simulations using the large 64 GB network
 configuration.  See attached two PDFs:

  - [https://trac.torproject.org/projects/tor/attachment/ticket/9166/sjm217
 -utp-64GB-seeds-combined.pdf sjm217-utp-64GB-seeds-combined.pdf] compares
 two runs with uTP for none of the links to two runs with uTP for all
 links.  The two runs using the same configuration use different random
 seeds (using `scallion` vs. `scallion -s 2`).  The motivation for this
 experiment was to see if the large 64 GB network configuration shows more
 significant performance differences than the small 16 GB network
 configuration, and to see if differences are real or random.
 Unfortunately, it looks like differences are mostly random.

  - [https://trac.torproject.org/projects/tor/attachment/ticket/9166/sjm217
 -utp-64GB-traffic-combined.pdf sjm217-utp-64GB-traffic-combined.pdf]
 compares the runs with seed 1 to similar runs that put additional non-Tor
 TCP traffic on the Shadow network.  Additional TCP traffic is produced by
 adding a second instance of Shadow's filetransfer plugin called traffic,
 making all clients perform requests to fileservers directly, and removing
 all `".*[traffic-.*"` lines from `scallion.log` before making graphs.  The
 motivation for this experiment was to see if additional network load has
 any effect on Tor performance.  Looks like this is not the case.

 I'd like to do one more experiment: can Shadow somehow output what amount
 of traffic uses TCP vs. UDP?  I'd like to re-run the simulation in a small
 or tiny network with uTP enabled and disabled, to confirm that
 enabling/disabling uTP actually worked.  Rob, any idea how Shadow could
 provide this information?

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/9166#comment:10>
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